drive: Event logger for chrome:drive-internals.

chrome/browser/chromeos/drive/drive_system_service.h

Index: chrome/browser/chromeos/drive/drive_system_service.h
diff --git a/chrome/browser/chromeos/drive/drive_system_service.h b/chrome/browser/chromeos/drive/drive_system_service.h
index 50e55da45b72a9d786aff0eb5b78025459ffb732..4920f9a0fd2b822934dfd099bb515a3d599dd166 100644
--- a/chrome/browser/chromeos/drive/drive_system_service.h
+++ b/chrome/browser/chromeos/drive/drive_system_service.h
@@ -29,9 +29,10 @@ class DriveCache;
 class DriveDownloadObserver;
 class DriveFileSystemInterface;
 class DriveWebAppsRegistry;
-class FileWriteHelper;
 class DriveSyncClient;
 class DrivePrefetcher;
+class EventLogger;
+class FileWriteHelper;
 class StaleCacheFilesRemover;
 
 // DriveSystemService runs the Drive system, including the Drive file system
@@ -112,6 +113,7 @@ class DriveSystemService : public ProfileKeyedService,
   bool push_notification_registered_;
 
   scoped_refptr<base::SequencedTaskRunner> blocking_task_runner_;
+  scoped_ptr<EventLogger> event_logger_;
   DriveCache* cache_;
   scoped_ptr<google_apis::DriveServiceInterface> drive_service_;
   scoped_ptr<google_apis::DriveUploader> uploader_;